Automatic transmission



July 15, 1952 E. J. FARKAS ETAL 2,603,109

AUTOMATIC TRANSMISSION Filed Dec. 13, 1946 4 Sheets-Sheet 2 E. J. FARKAS ATTORNEYS.

July 15, 1952 E. J. FARKAS ETAL 2,603,109

AUTOMATIC TRANSMISSION Filed Dec. 15, 1946 4 Sheets-Sheet 4 E. J. FARKAS J. F. SWIFT I INVENTORS 6 ZZ Z r BY 4; M,

ATTORNEYS.

Fatenteci July 15, 1952 PATENT 0 F FICE' Delaware overrunning during forward second speed operation, yet which will provide a positive drive through the transmission in the reverse direction when it is desired to use the engine for braking in low speed during downhill operation.

Additional objects will be made more apparent as this description proceeds, particularly when considered in connection with the accompanying drawings, in which:

Figure l is a longitudinal sectional view through the transmission.

Figure 2 is a transverse cross sectional view through the forward speed brake mechanism, taken substantially on the plane indicated by the lines 22 of Figure 1, withthe'forwardbrake band in its off-position.

Figure 3 is a transverse cross sectional view through the reverse speed brake mechanism, taken substantially on the plane indicated by the line 3--3 of Figure 1, with the reverse brake band in its o l-position.

Figure 4 is a plan View of the supporting plate for the brake actuating subassembly.

Figure 5 is a transverse cross sectional view through the reverse speed lockout mechanism, taken substantially on the plane indicated by the line 5-5 of Figure 1.

Figure 6 is a longitudinal vertical schematic drawing of the transmission.

Figure 7 is a longitudinal vertical schematic drawing of a modified transmission.

Figure 8 is an enlarged fragmentary longitudinal cross sectional view illustrating the twoway overruning clutch of the modification shown diagrammatically in Figure 7 It will be noted that the general construction of the transmission is shown schematically in Figure 6, and that certain portionsthereof correspond generally to portions of the transmission shown in the above-mentioned copending application, reference being made thereto for a more 4 I4 and carries clusters of planet pinions 32, 33 and 34. Planet pinions 32 mesh with a sun gear 36 carried by the clutch carrier 21, planet pinions 33 with a sun gear 31 mounted upon the second intermediate shaft I4, and planet pinions 34 with the sun gear 38 carried by the load shaft I6. In order to transmit torque through the multiple planetary gearing system in the forward direction, an overrunning clutch 35 is connected to the planet carrier 29. The overrunning clutch is adapted to be selectively connected to the transmission casing by means of the forward speed brake mechanism 4|, to be described more in detail hereinafter. To condition the transmission also be more fully described later.

detailed description and illustration of such comv a torque converter I1 having an'impeller I8' driven directly by the drive shaft I2, a turbine I9 connected directly to the first intermediate shaft I3, and a reaction member 2I connected to a. flange 22 of the transmission casing through an overrunning brake 23. The overrunning brake 23 normally allows the reaction member II to take the reaction of the fluid circuit, but when the output torque drops below the input torque allows the reaction member to overrun so that the torque converter will function as a fluid coupling.

The first and second intermediate shafts I3 and I4, respectively, are mounted for relative rotation by means of the bearings 24, and the first intermediate shaft I3 is provided with an extension 26 adapted to be operatively connected to a clutch carrier 21 by means of a second speed clutch 28. The clutch carrier 21 is also adapted to be locked to a planet carrier 23 by meansof a third speed clutch3l. The second and third speed clutches are adapted to be actuated automatically by hy draulic mechanism to be mentioned later.

The planet carrier 29 is mounted for rotation about-the axis of the second intermediateshaft The second and third speed clutches 28 and 3I are actuated by pistons 43 and 44 housed within cylinders 46 and 41 respectively, and fluid under pressure for operating the clutches is supplied by a fluid pump 43 driven by the load shaft I6 and transmitted through conduits 49 and 5| to the cylinders 45 and 4'! respectively, see Figure 6.

The flow of fluid through conduits 49 and 5| is controlled by a sleeve valve 52, the position of which'is regulated by a centrifugal governor 53 mounted upon the clutch carrier 21. In low speed, the governor controlled valve 52 blocks the flow of fluid through both conduits 49 and 5| and, accordingly, neither the second or third speed clutch is operated. Power is then transmitted from the drive shaft I2 through the torque converter I! to the first intermediate shaft I3. An overrunning clutch 54 is provided between the flrst and second intermediate shafts I3 and I4 and enables the second shaft I4 to be driven by the first shaft I3, but permits overrunning when the speed of the second shaft I4 exceeds that of the first shaft I3. The power flow is then through sun gear 31, planet pinions 33 and 34, and sun gear 38 to the load shaft I6, driving the latter in the forward direction in the low speed range. Inasmuch as the torque converter I'I transmits torque and speed in a continuously variable fashion within its operating limits, which may be in the neighborhood of 3 or 4 to 1, adequate torque for all starting and high load conditions is available and it is possible to design the multiple planetary gear set so that the low speed gear ratio is relatively small. For example, the low speed gear ratio may be approximately 2 to 1, even when used with a relatively low rear axle ratio, with the result that the steps between low and the succeeding gear ratios can be held to a minimum to achieve smooth shifting and maximum performance under all conditions.

The transmission is automatically shifted to I1 to the first intermediate shaft I3, and thence throughrthe second speed clutch 28 and clutch carrier 21 to the sun gear 36. A reduction is then effected through planet pinions32 and 34 and sun. gear 38. to rotate the. load :shaft; IS in the. forward direction at an intermediate -.or secondspeed ratio. A; second speed-gear ratio in theneighborhood of 1.4 m1 has been found .satisfactory, and inasmuch as this ratio is relatively. close to both the low speed ratio of approximately 2.to.-.1 and the high speed ratio of 1 to 1, the transition steps are held to a minimum. Since the steps are small, and the torque. converter.- incorporated in the power train during-allv speed ratios, the shiftsbetween the variousspeed ratioscan beeifected with extreme smoothness.

When the rotational speed of the clutch carrier 21. has. increased a further predetermined. amount, the governor controlled-sleevevalve. Z- isshifted to a position establishing fluid commu-; nication through conduit 5| to the third speed clutch cylinder d1. Piston 44 in the cylinder applies :the third speedclutch 3| and results in the rotation as a unit of the clutch carrier 21, planetcarrier 29, and the triple planetary pinion. Accordingly, a direct drive is established through. thegear portion of the transmission, modified onlyby the flexibility of the. torque converter, which remainsin the power train.

Itwill be noted that'during second and third speedoperation, the second intermediate shaft l4. rotates in the forward direction at a speed. exceeding the speed of the first intermediate shaft 13, this being permitted by the overrunning clutch 54.. It will also be. noted that noneof the shifts. are timed shifts, thus further promoting smooth operation. p

Although the. production costof the present transmission isslightly higher: thanthat of the transmission. shown in the above-mentioned co-. pending application, the operating performancev and the smoothnessv obtained are considerably improved, thus providing a transmission satisfactory for themost discriminating motorist.

The ease of operation of the present transmission is alsoenhanced by the brake friction means. usedto place the transmission in forward and reverse. speeds. For a disclosure of this mecha-- nism, reference is made particularly to Figures 2,3,: and 4, Figure 2 showing the forward speed brake mechanism and Figure 3 the reverse speed brake mechanism. The forward speed brake mechanism. shownin Figure 2 will first be de-.. scribed.

A rotatable brake drum 6! .is connected to the overrunnin clutch .39. and is adapted to'be .re-. tarded by a brake band .62 comprising a number oflconvolutions, in this instance 2% turns, encirclingthe brake drum andadapted to be con-. tracted into frictional engagementtherewith. The inner surface of the brake' band is preferably copper plated. to provide smooth engagement with r the Ldrumand additional wearing qualities. One endxof the-brake band is formed with a flange 63 received within-an anchorblock '64 and held therein-by flaring-the end of the'flange; The anchor block seats within a-recess 66 formed in a boss-in the transmissioncasing l I and is held against longitudinal displacement by a locatingpin- 61; Adjacent the brake band a 62, the inner surface of thetransmissioncasing-H is machined toprovide-a smooth accurate surfaceupon which the-brake band seatsinitsreleased position.- The band is originally stressed so as to have a natural; tendency to expand a into released a position 'ad-' jacent :the casing;

Theopposite or unanchored end of the band is provided'with an elongated slot 68 into Whichtheupper endtS' Qfi an actuating lever 1 'lpro1ects-.-=

Theiever-ii sanctum q-shapedandzi-s pivotak...

lyvm'ounted at-.-its lower. and upon. apivottpin 12 carried in a boss I3. formed: upon the; supporting plate 14; The plate! Mihas flanges. 16.. adaptedvtooverlap. an opening 11-. formed inthe; 1135.9 .18 iof; the transmission casing, being; bolted, thereto: by.- bolts. 19; A rib. 8| is formed adjacent the-13.010101.

the. actuatinglever- H andprovides a :supportforz;

one: end of a: coil spring 82..the. opposite/end. of; which is attached toa.stud-.83 extending-upwards.- 1y fromthe supporting. plate. 14., A coil. springzfll. continually urges; the. actuatingileyer: and-.the brake band in a directionztor contractz-the'handi andapply the latter to .the brake: druiruil.v

torelease the brake-band. Cam is mounted;

upon ascamshaft '81,- bestshown in; Figures #1 and 4 as extendinglongitudinallyof the transmission:

and journaledin fiangesBB. and .89.extending.- A

upwardly from opposite ends of v the supporting.;--.

An arm 91 is fixedly mounted upon .th'e .cam.-- shaft 81 and carries, a, connection 92. at 1 one :end: adapted to be connected to-suitab1e:linka'g'e-(not shown) controlled by a manually operated 'lever. preferably mounted uponi the-steeringzcolumn ofz; the vehicle. Referring again tosFi'gurefi, itIlWiII-p be noted :that the periphery-of thecarn .8.6. isaso-. formed as :to provide three angularlyspa'ceddepressions 93, 94-and95.. The depressions93,:Ski;-v and 96. are spaced difierent radial; dimensions fromthe camshaft :81 and: engage: the cam follower 84 to provideforward, neutral and-reverser positions respectively. In addition; th'e-dBPIBS-" sions function toindex the cam between its .operative positions. p In the position shown in Figure 2, the cam fol--5- lower 84upon theactuatinglever is eng-agedgby thesurface Qdofthecam, and since this is'the. =1

predeterminedposition for reverse speed operae tion, the actuating lever 1 l is moved against: the action. of thecoilspring82 to release the brake..- band v62 .from engagement'with drum 61, thus.- rendering. the forward speed brake mechanism:

inoperative.- It will be seen that co,unterclock-.v

wise. rotation of cam 86 .to the neutral position, indicated by the reference character 94 also rendersthe forward speed. ibra'ke mechanism in. operative,-. and that further counterclockwise.

,rotationto. the forward speed position indicated under-certain conditions. To avoid this, theslot- 68in theend' of the band is made slightly longer than the upper end 69 of the actuatinglever; so that the brake-band is positively released from the. brake drum when the actuating: lever is moved by the camagainst the actionof the coil spring.

Figure 3 illustrates the reversespeed brakingmechanism, which is generally similar-=in-con-l struetion'to that of-the forward speed bralring,- mecnanismadescribedabove. In tnis viemthe camshaft 8'!v isshown'in' the same angular position as in Figure 2. the reverse speed band being on and the forward speed band being off. 'The reference character speed band which is. formed of spring steel and comprises 3% turns. The end I02 of the band is anchored in an anchor block I03 which, in turn, is mounted inthe transmission casing. The opposite end: of the band is formed with an elongated slot I04 intowhichthe upper end of the actuating lever I06 projects. The actuating lever is pivotally mounted upon a bossv I01 formed at one side of the supporting plate 'I4.' A brake applying spring I08 operates to contract the brake band IOI intofrictional engagement with the exterior surface of the clutch carrier 21 which functions as a brake drum.

The reverse speed cam I09 carried by the camshaft 81 is identicalin shape with the forward speed cam'86, but is mounted upon the camshaft in a reversed manner. The cam surfaces III, H2 and H3 engage the cam follower II4 carried by the actuating lever I06 in, the reverse, neutral and forward speed positions, respectively. The

cam is shown inits reverse position, and it will be noted that in this position considerable clear-.

ance is provided between the cam follower and the: cam so that the spring I08 is free to move the brake band into frictional engagement with the drum. Furthermore, the clearance between the cam and the cam follower provides for wear of the. brake band surface. The arrangement is such that no adjustment is necessary even though the brake bandv wears ;considerably .since the positioned diametrically opposite each other and.

in alignment with the cam followers upon the actuating levers. It follows that in this position the reverse speed band II is on and the forward speedband..62 is off. When the camshaft has been turned to a position such that cam surfaces 94 and I I2 are in alignment with the cam followecsboth the forward and the reverse speed bands will be released from their respective drums and the transmission will be in neutral. Similarly, when the forward speed cam surfaces 93 and I I3 upon the two cams, respectively, are arranged in alignmentwith the cam followers the forward speed band 62 is on and the reverse speed band IN is off.

.It will be seen that the entire brake actuating mechanism, both for the forward and the reverse speed brake bands, is mounted upon and carried by the supporting plate l4. With this arrangement the entire brake actuating mechanism can be assembled uponthe plate I4 as a bench assembly prior to the final assembly of the transmission, greatly simplifying and reducing the cost of the assembly since it is relatively simple to assemble the parts as a subassembly whereas it would be comparatively diificult because of space requirements to assemble the parts within the'transmission casing. After the subassembly hasbeen'completed, it is only necessary toplace IOI indicates the reverse with the guide member I21.

the camshaft in neutral. position so that each of the brake actuating levers is held in an onposition, after which the entire subassembly can be inserted into the transmission casing through Inasmuch as the brake bands 62 and IOI normally assume a released position due to their inherent resiliency, the upper ends of the brake actuating levers II. V

Inadvertent shifting of the manually controlled I shift lever to its reverse position while the vehicle is traveling forward may possiblyresult in serious damage to the working parts of the transmission. The present invention provides means automatically operabie to prevent such an ,oc-.. Referring now to Figure 5, it will be currence. noted that the arm 9i carried at one end ofthe camshaft 87 is formed with a quadrant shaped portion II8, the periphery of which is arcuate and formed with an eiongated arcuate slot IIIL.

Mounted in the side wall of the transmission casing II adjacent the quadrant shaped portion H8 of the arm is a reverse lockout assembly I2I. This assembly comprises a cylindrical housing I22 screwed into a threaded opening formed in the transmission casing and provided with a cylindrical bore I23 therein. A piston I24 is reciprocably mounted within the bore I23 and carries at its inner end a cylindrical extensio I26 piloted in a guide member I21.

The piston I24 is adapted to be urged inwardly against the action of a coil spring I20 by fluid pressure in the fluid chamber I29 formed in the housing at one end of the piston. Fluid under pressure from the fluid pump 48 is directed to the fluid chamber I29 through a fluid conduit- I3I formed in the transmission casing.

During normal operation of the vehicle in a forward direction, fluid pressure is generated by the fluid pump 48 and supplied to the fluid chamber I29, forcing the piston I24 inwardly so that the extension I26 at the end of the piston is moved into the slot II9 formed in the portion II8 of the arm Ill. The movement of the piston under the action of fluid pressure is limited by engagement of the shoulder I32 on the extension lockout assembly thus in operation, movement of the arm 9| between neutral and forward positions is permitted, as will be seen from an examination of Figure 5, but engagement of the extension I28 with the end of the slot H9 pree vents movement of the arm to the reverse posi tion. Inasmuch as the fluid pump 48 generates fluid pressure at all times during forward movement, being driven by the load shaft I6, shifting, of the transmission into reverse during for:

ward speed of the vehicle is effectively prevented.

On the other hand, when the vehicle is stopped the fluid pump is inoperative and no fluid pres,- sure is supplied to the reverse lockout assembly. The return spring I28 is then effective to'move the piston outwardly until the stop I33 carried by the piston engages the end of the housing, in which position the extension I26 is completely retracted out of the slot I I9 in the arm. The shift .lever and the arm 9I can then bemoved to reverse With the reverse .=position. The lockout-mechanism is thus entirely automatic and requires-no attention on thepart'of the operator, yet iseifective to prevent possible damage to the transmission mechanism by making it impossible to inadvertently shift-the transmission into reverse when the vehicle is traveling in a forward direction.

In the form of the transmission shownin Figures 1 to 6 inclusive, second speed can be used as a hill brake toobtain the benefitsofengine braking. In addition, second speed provides a solid drive back :to the torque converter and the engine .to enable the latter to be started when stalled by pushing the vehicle. As mentioned before, among theaolvantages of thepresent invention is the fact that the particular combination enables the various gear reductions to be relatively low, thus achieving extreme smoothness in operation. This means, however, that .the gear reduction in second speed may not be sufilciently high to provide adequate engine braking for hill operation. It is thus desirable to provide means whereby low speed can be used to .provide engine braking at the requisite gear reduction. It will be noticed, however, that the overrunning clutch 54 between the'first intermediate shaft I3 and the second intermediate shaft I4 prevents the transmission of power through the transmission in the reverse 'directionfr'om the load shaft I6 to the driveshaft I 2Iinlow speed, since'the clutch 54 overruns when the speed of the shaft I4 exceeds that of the shaft I3.

The modification of the invention shown in Figures 7 and 8 is particularly designed to en- /way overrunning clutch I36, and that the low sun front gear 31 and its associated planet pinions 33 are formed with helical or spiral teeth.

As best seen in Figure 6, the first intermediate shaft I3 is provided with an end flange I31 which carries a hub I38 having a splined enlargement I39 at the opposite end upon which are mounted the'plates of the second speed clutch 28. An auxiliary hub member MI is removably mounted "'withinoneend of the hub I38.

Mounted for rotation with the second intermediate shaft I4 is a sleeve I42, which is preferably splined to the shaft and which is held against axial movement, relative to the shaft by,

a retaining ring I49. The forward end of shaft 14 is reduced'in diameter and is piloted in th'e ad jacent end of shaft I3 by bearings I45. The construction is such that a limited amount of axial reciprocation of shaft I4 in the transmission is permitted, for a purpose which will appear "later. The sleeve I 42 is formed with an integral radially extending Web I43 which, in turn, supports an annular axially extending rim I44. The web I43 extends slightly beyond the rim N54 to form an annular shoulder 'I 46.

.In the annular spaces thus formed between the sleeve I42 and the rim I 44 -on opposite sides of the Web I43 are mounted a pairof spring clutches I4'I-and I48. These spring clutches are of C011.-

The

' ventional type and embody a number of convolu- .tions of spirally wound spring steel wire. adjacent ends of thespring clutches I41 and I43 are :bent to form tabs I 49 and I5I, respectively.

These tabs extend into openings, formed in the annular bearing washers I52 and I53, respecsides of the web I43 of the sleeve I42.

The opposite ends of the spring clutches I41 and I48 are similarly formed with tabs I54 and I56, respectively, which are received within openings formed in the first intermediate shaft-I3 and in the auxiliary hub I4I which, of course, is carried by the shaft I3 through the intermediate hub I38. A coil spring I5! is positioned between the shoulder I46 formed upon the web I43 of the sleeve and a shoulder I58 formed in the hub I 38. The coil spring normally functionsto urge the reciprocable sleeve I42 to the right as seen in Figures 7 and 8 and to thus maintain frictional engagement between the bearing washer I53 and the adjacent face of the web I43. I

In operation, the transmission functions as follows: 'When the vehicle is running in low speed forward, the first intermediate shaft I3,.which is driven from the vehicle engine through the torque converter I1, transmits power to the second intermediate shaft I4 through the mediumof the hub I38, auxiliary hub MI, spring clutch =l48, bearing washer I53, and sleeve I42. This drive is made possible by the fact that the spring clutch I48 expands into frictional engagement with the rim I44 when actuated. Inasmuch a the coil spring I51 urges the sleeve I42 to the right'so that the web I43 frictionally engages the bearing washer I53, rotation of the tab I5I at the opposite end of the spring clutch I48 by the auxiliary hub I4I tends to unwind the convolutions of the spring clutch and to expand the latter. During low speed operation, the spring clutch I41 overruns, since the coil spring I5! holds the web I43 out of frictional engagement with the bearing washer I52.

In second speed, the drive is through the second speed clutch 28, by-passing the two-way overrunning clutch I36 and then through the clutch carrier 2'! to the sun gear 36, planet pinions-32 and 34, and sun gear 38 to the load shaft 16. During this second speed operation, thesecond auxiliary shaft I4 is permitted to run faster than modified transmission is identical with that-of the form shown in Figures -1 to .6 inclusive, inasmuch as the entire planet gear locks up and rotates as a unit to deliver power in the forward direction at a unitary ratio.

When it is desired to transmit power through the transmission in the reverse direction, as durin taxi starts or when using the engine as a brake during downhill operation, the modified transmission shown in Figures? and 8 can be placed ineither first or second speed whereas the form shown in Figures 1 to 6 inclusive will function to, transmit .power in the reverse direction only in second speed and not inlow. In view of the fact that the gear reduction in secondspeed is only in the neighborhood of 1.41 to 1, and thus relatively low in comparison with normalsecond speed gear ratios, under some circumstancesinsuffiicent engine braking is obtained insecond speed and recourse must be had to the higher gear ratio of low speed. The DGWGlzfiOW under the latter circumstances is fromtheJload shaft I6 to the load shaft sun gear as and through the planet pinions 34 and 33 to the sun gear 3! on the second intermediate shaft I4. Inasmuch as the planet pinions 33 and the sun gear 31 are helical gears, a longitudinal or axial thrust is imposed upon the second intermediate shaft I4 in a leftward direction as seen in Figures 7 and 8. As mentioned above, shaft I4 is mounted for limited axial movement, and the thrust of the helical gears moves the shaft I4 and the sleeve I42 against the action of the compression coil spring I51. This results in mov'mg the web I43 of the sleeve away from the adjacent radial surface of the bearing washer I53 associated with the spring clutch I48 so that there is no longer any frictional engagement between the washer and the web. This renders the spring clutch I48 inoperative. At the same time, however, the web I43 is moved into frictional engagement with the bearing washer I52 associated with the spring clutch I41. Thus actuated, the spring clutch I41 is expanded into frictional engagement with the rim I44 of the sleeve and also with the bore I59 of the hub I 38. A positive power path is thus established from the shaft I4 to the shaft I3. This enable the engine to be used as a brake and, in addition, enables the transmission to be placed in low gear during taxi starts when pushing the vehicle to start a stalled engine.

From the foregoing it will be seen that the two-way overrunning clutch I4I not only permits the necessary overrunning between the shafts I3 and I4 when the transmission is operating in the forward direction, but also enables 10w gear to be used as an engine braking gear ratio. Without a mechanism of this type, it would be impossible forward are obtained with a single multiple I planetary gearset. In other words, the two-way overrunning clutch provides a drive in the forward direction at low speed and overruns during forward second speed operation when the speed of the second intermediate shaft I4 exceeds that of the first intermediate shaft I3, yet permits a positive drive from the same shaft I4 to the shaft I3 in the reverse direction without overrunning, to provide engine braking in low gear.

It will be understood that the invention i not to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined in the appended claims.

What is claimed is:

1. In a variable speed power transmission, in combination, a housing, a drive shaft, first and second coaxial intermediate shafts, and a load shaft, a torque converter having an impeller driven from said drive shaft, a turbine operatively connected to said first intermediate shaft, and a reactor connected through an overrunning brake to said housing, a multiple planetary gearing system between said second intermediate shaft and said load shaft comprising planet pinions rotatably supported about the axis of said second intermediate shaft and respectively meshing sun gears carried by said intermediate shaft and said load shaft, a clutch carrier rotatably supported about the axis of said intermediate shafts and supporting one of said sun gears, an overrunning clutch between said first and second intermediate shafts, friction clutch means carried by said clutch carrier for selectively connecting together 12 said first intermediate shaft and said clutch carrier, and additional friction clutch means for selectively connecting together said clutch carrier and said planet carrier.

2. In a variable speed transmission, in combination, a driveshaft, first and second intermediate shafts, and a load shaft, a multiple planetary gearing system between said second intermediate shaft and said load shaft comprising planet pinions rotatably supported about the axis of said second intermediate shaft and respectively meshing sun gears carried by said second intermediate shaft and said load shaft, first clutch means providing a positive drive from said first intermediate shaft to said second intermediate shaft in one forward speed ratio and permitting said second intermediate shaft to overrun said first intermediate shaft during forward speed operation in another speed ratio, and second clutch means interconnecting said first and second intermediate shafts automatically providing for power transmission from said load shaft to said second intermediate shaft in said first-mentioned speed ratio.

3. In a variable speed transmission, in combination, a driveshaft, first and second intermediate shafts, and a load shaft, a multiple planetary gearing system between said second intermediate shaft and said load shaft comprising planet pinions rotatably supported about the axis of said second intermediate shaft and respectively meshing sun gears carried by said second intermediate shaft and said load shaft, first clutch means providing a positive drive from said first intermediate shaft to said second intermediate shaft in one forward speed ratio and permittin said second intermediate shaft to overrun said first intermediate shaft during forward speed operation in another speed ratio, and second clutch means interconnecting said first and second intermediate shafts automatically providing for power transmission from said load shaft to said second intermediate shaft in said first-mentioned speed ratio, said first and second clutch means comprising overrunning clutches disposed between said first and second intermediate shafts and reversely arranged with respect to each other.

4. In a variable speed transmission, in combination, a driveshaft, first and second intermediate shafts, and a load shaft, a multiple planetary gearing system between said second intermediate shaft and said load shaft comprising planet pinions rotatably supported about the axis of said second intermediate shaft and respectively meshing sun gears carried by said second intermediate shaft and said load shaft, first clutch means providing a positive drive from said first intermediat shaft to said second intermediate shaft in one forward speed ratio and permitting said second intermediate shaft to overrun said first intermediate shaft during forward speed operation in another speed ratio, and second clutch means interconnecting said first and second intermediate shafts automatically providing for power transmission from said load shaft to said second intermediate shaft in said first-mentioned speed ratio, said first and second clutch means comprising overrunning clutches disposed between said first and second intermediate shafts and reversely arranged with respect to each other, said sun gear carried by said second intermediate shaft and the planet pinions meshing therewith having spiral teeth producing an axial thrust on said second intermediate shaft when power is transmitted from said last-mentioned planet pinions to said last-mentioned sun gear to control the operation of said overrunning clutches.

EUGENE J. FARKAS. JOHN F. SWIFT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Wilson Nov. 15, 1932 Farkas Oct. 9, 1934 Cotterman Jan. 24, 19-39 Number 

